In recent years, over the top video (OTT-V) has become a mainstream of a streaming service via the Internet, and as a fundamental technology thereof, Moving Picture Experts Group-Dynamic Adaptive Streaming over HTTP (hereinafter, referred to as “DASH”) (MPEG-DASH) using a HTTP in which a supply side is connected with a reception side in a point to point manner, similarly to browsing of a web site or the like has been known (for example, see Non-Patent Literature 1).
In the DASH, an adaptive streaming technique is implemented. In other words, a content supply side has a system capable of supplying a plurality of streams that include content of the same subject but differ in an image quality or an angle of view size, and a reception side is configured to switch and view an optimal stream according to according to a communication environment of the Internet or a capability or a state of the reception side.
In the DASH, as information enabling the reception side to adaptively switch a stream, a metafile called a media presentation description (MPD) is supplied from the supply side to the reception side. An address (url information) indicating a server of a supply source of streaming data (media data such as audio/video/subtitle) divided into chunks is described in the MPD.
The reception side can access the server based on the url information and acquire and reproduce HTTP-transmitted streaming data.
FIG. 1 illustrates an example of a configuration of a content supply system that delivers content in a streaming manner based on the DASH.
A content supply system 20 includes a content management server 21, a DASH segment streamer 22, and a DASH MPD server 23 which are arranged at a side at which content is supplied and a DASH client 30 arranged at a side at which content is received and viewed. Although not illustrated, there are assumed to be a plurality of DASH clients 30.
The content management server 21 manages content supplied to the reception side, generates a plurality of pieces of streaming data having different bit rates from content of the same subject, and outputs the generated streaming data to the DASH segment streamer 22.
The DASH segment streamer 22 temporally divides streaming data of content into segments, holds each of the segments as a file, and notifies the DASH MPD server 23 of an address of the files. Further, the DASH segment streamer 22 unicast-delivers the file of the segmented streaming data in response to a request from the DASH client 30 of the reception side via the Internet 11 as an HTTP server.
The DASH MPD server 23 generates an MPD in which, for example, an address of the DASH segment streamer 22 serving as the supply source of the files of the segmented streaming data is described. The DASH MPD server 23 unicast-transmits the MPD to the DASH client 30 via the Internet 11 in response to the request from the DASH client 30 of the reception side as the HTTP server.
The DASH client 30 of the reception side receives and reproduces content, and accesses the DASH segment streamer 22 serving as the HTTP server based on the MPD acquired from the DASH MPD server 23 and receives and reproduces the files of the segmented streaming data.
There are cases in which a cache server is installed on the Internet 11 to cache the unicast-transmitted MPD, the files of the segmented streaming data, or the like and undertake an operation of the DASH segment streamer 22 or the DASH MPD server 23.